Telephone signaling equipment



L. F. MoREHou TELEPHONE SIGNALIG EQUIPMENT Oct. 13, 1925.

Fned sept. l16. 19,19 4 sheets-shut 1 A INVENTOR. EMM/awe BY A TTORNEY.

Oct. 13,1925.l 1,557,079

L. F. MOREHOUSE TELEPHONE` SIGNALING EQUIPMENT Filed Sept. 16, 1919 4 Sheets-Sheet 5 im BY i ATTORNEY.

L.. F. MoREHousE TELEPHONE SIGNALING EQUIPMENT Oct. 13l 1925- 1N V EN TOR.

TTORNEY.

4 Sheng-Sheet 4 L'/oleallse BY Filed Sept. 16, 1919 Patented ct. 13, 1925.

-L'YM-lrN r; Monsnousn, or MoN'rcnA11 NEW JERSEY, AssmNo-Rvro Mirino/Anamne- PHQNEANDTELEGRAHI conrnnmn ooRroRAm-Ionyor "NEW yong.

Application filed-September 1.6191-9. Serialflo., `324;;l49.`

To all whomnz't Y77u77/ cio-mem; i t 7 Be it known that I, LYMANF. .M onnrronsna residing at Montclaiig, inthe :county ofEssex ,andl State :of'NeW Jersey, have invented cert-ain Improvements in Telephone ing .'Equipnientnof which 'the i following; is a specification.

This inventionrelates to telephone systems and more 4particularly totmeans for, titans initting supervisory and other Asignals-incidental touthe establishment of, connections over 'telephone lines. Y

A feature ofthe invention, istheiproyision 'i of `rneans whereby. supervisory,-signalsniay betransmitted over `the telephone line, Without interfering With'the use Potthe .metallic circuit of,` the `line for ,the transmission yof metallic circuit Morse signals.` ,v l e Another feature-bf the inventiony is the provision `vof :means whereby supervisory signals unay. be transmitted-031er :thetelephone line, without the use of apparatus at intermediate stations to relaysuch Super- .visor-y signals.

Another feature of the ,inuention has reference tothe prouisiolnoii means-whereby the `supervisory i signa-ls.'Y off a plurality oit. tele phone "lines may be transmitted louen one -O the lines,thus leaning the ,Irernaining linesof the gnoup, free-for ther purposes.

A further feature Vof the innention .relates tothe provisionfof oneor incre carrier chan,- nels. inconnection with a telephone line, `fer the purpose ottransmitting the "various supeltfinisory signalsr vnecessary in vthe estab,- lislnnent of, .connections over Athe line. i Y

A still further afeatureof Athe invention .is the provision, in connection With Ione tele.-

`)hone line of ,avr-group, of a suiicient num lier ot channels having frequencies lying without the voice range, Ato' transmit 4the necessary supervisory signals `for .all of the lines ofthe group.

`Other and further objects of the invention will clear, from the following nde.- scriptinn lwhen read in connection with .the accolnpanyinfg1 drawing, in. which Figure l Vis"asdiagrarn,oi". anl embodiment o\the invention, in, which a carrier .channel is provided for .theringing siguialsiof a ringdown` toll, line circuit;

Figure 2 isa diagram'lillustrating the invention as. embodied. lin afsysteni in which a suficient number of carrier Achannels are fislatef with 2112 l150,511 lire It@ trees-*rit the ningdownsignals of al plurality lof ringdown tol-lline circuitsgnnd, l 7

' ism/v3 en@ 3 la 'together @Qnsttute diagram-illustrating ,the invention as applied to a,callicircuitltollfline. v v

rllefenringk .to Eigure l, L1 designates `a ringdown toll line circuit terminating :in jerks Ji end-J1@ whereby wnnedtiosns wey be made-i` to Various',subscribery stations, v In order t0. transmit frire-dew Sisnels @ver the line LM bnanches are led off; from, :the line ``at each. terminal station,` through, :high pass `filters- `HF `:and to :carrier apparatusor translating transmittedl iringdo'xyn signals into carrier currents andv for translating Yreceiyed,r carrier currents into ring'donfn signals. The filters HFand HF are preferably of the broadband type oflilte disclosed lin U. S. patents to George AGarnp teu, ,1,227,1:13-.and7 1,227,114, `dem,1x/,tw 22, .19177. Thepurpose .ot these filters Aisato ,pre- ,Vent ytelephone currents., from` sbeing'diyerted from .the line into .the .carrier apparatus.

:In order togsimilarly prevent-tbe carrier currents from being 1tramsnlitted;Y to the telephone drop instead of to theanrier appa` ratus, .low 'pass .ilters LF and LF fareneluded in the terminal connectionslojftllie@toll line .Lm as ,indicarted,y These :filters Yarea-lso of the broadband; typeydisclpsed, jin ithe aboue-mentQIlQd patentsA "to George A. .Campbell and are. so designed aus 11,0` transmit "a ,band of; lfrequenties ,7 enteridingV over thevoioe r.ange..` 7 i The tnansrn'tting carrier .apparatuscoinprisesloscillators or generatorsg,Gr1 .andGlb and ,ampli-,fiers TA1 and TA1(- Thegenera: tors .ane ,preferably `of the `Well;l'miown vacuum tube l.oscillator type, althllgh ,any Well-known; means fior producing oscillating currents. may be, used; Thie arriplrs @Ar and m11 2me/.beef any wenn@ @has eater, but preferably are vanuiun. tube;- ern,- pli-fiers.

The. reserving carrier apparatus comprises am ,Bste-BA1 and. :RA-fi, dei-@m1255331 `fwd D1; and receiving relays i llhe amplifiers BA1 "andE llel sterrrefembly ,Vacuum .tube M.arnplilfiers, `similar toy lthe Vapr/n,- pliers 'BA1 and ilAglr kand` lunction toamr plify. received carri/ er currents; The detectors D1 and D1A maygbeotanyfoi ,the Well'f known typesfelnployed in nadie; transmise Sin, andere prfre-bly www mbsdetetOfS- terrines. en@ RJ er@ 'direct current relays which are included in the output circuits of the detectors.

Further details of the apparatus may be relay, upon being operated, opens the cir-v cuit of the line signalL to prevent its operation. `When the Aoperator y transmits ringing current to ,thetoll line overA the tip and ring contact of the'j ackJ 1, the ringing responsive relay l1 is operated'and over its front ,contact completes the circuit ofrelay 12.V Relay 12, upon'being energized, 'connects the carrier branch CB1 over its front contacts to the amplifier TA1 so that oscillations'from the generator'G1 are amplified by the amplifier TA1 and VVtransmitted through the high pass filter HF to the toll line; At tlie're'ceiving station the carrier currents transmitted over the' line pass through the high pass filter HF and over the back contacts of the relay 12 to the amplifier RA1. The amplifier BA1. amplifies the received carrier currents which are detected by means of the detector D1', so that the direct current relay R1 is operated. The relay R1 atits upper front contact completes a locking circuit, from ground throughv its locking winding over the extreme lefthandk back Vcontact of relay 10 and through the lamp Lf yto battery, thereby vcausing the lamp toy glow, to call the attention of the inward operator atthe east end of the line. 1 f 1 i a A .When theinward operator answers the call thus `indicated,'the plug of autoll -cord is inserted in thejack J1', thereby operating the sleeve relay 101, whichfopensthe locking circuit of the relay R1 vthrough the lamp L1, so that the lampis retired and the relay R1restored to normal. f If,'withthe circuit in this condition, it .shouldbe necessary for the operator at the westl end'of the line to recall the operator at they east end of the line, ringingcurrent will be transmitted to the relay 11"with `theKV same results aspre- 'viously described, up to the'point where ,the

relay R1 is operated infre'sponseto detected carrier currents.L The relay R1', upon now being energized, completes a Ashunt about the high resistance of the winding of the sleeve relay 10" from groundover'the lower front Acontactv o f Irelay R1A and over the right-hand front contact of relay 10. This operation,decreases the, resistance in the sleeve circuit suflicientlyl to operate a marginal relay in the sleevecircuit of thetoll cord, thereby operatingk the supervisory lamp of the toll cord. Inasmuch as the circuits and apparatus associated with the marginal relay and supervisory lampV above referred to are part of a standard 'toll circuit well-known in the artI and are not a part of the present invention, these features are not illustrated herein. It will benoted that the sets of apparatus associated with the east and west ends of the toll line L1 are identical in character, so that the circuit is a twoway circuit and can be operated in either direction. lThe operations incident to transmission in the opposite direction are similar to those already described and need not be further considered. 1

Figure 2 illustrates an arrangement'in which the ringdown signals for a plurality of tolllines maybe transmitted over"carrier channels associated with one of the toll lines, thereby leaving the remaining toll lines available for the superposition of carrier channels for other purposes.` In this form ofthe invention the carrier branch GB, which includes the high pass filter HF, is associated with transmitting channel TL and receiving channel RL through a balanced transformer arrangement X, of a well-known type. In Vorder that the channels TL and RL may be conjugate'with respect to each other, so that yelectrical disturbances arising in the one circuit will not affect the other, the balancing network N1 is provided, said net work being sodesigned as to balance the filter HF, the toll line L1 etc. The transmitting channel TL is provided with transmitting branches TL1, TL1, etc., leading to transmitting carrier apparatus for toll lines L1 yand L2, etc. The toll lines other than the line L1 are not illustrated, it being sufficient'for'the purpose of -understanding the invention to` illustrate merely the carrier apparatus associated therewith. Ina similar manner the receivingchannel RL is provided ywith receiving branches RL1, RLg, etc., leading to the receiving carrierapparatus for the several toll lines. The transmitting and receiving carrierapparatus associated'with the vseveral transmitting 'and receiving branches is similar Lto that already describedin connection with Figure 1.

Further details of the apparatus will be vclear yfrom thedescription of the operation,

which is as follows: Y

' Upon the insertion of aplug in the jack J 1, sleeve relay 10 is energized and opens the circuit ,of the lamp L1. Upon the "transmission of ringing current to the line L1, ringing responsive relay 11 is operated, thereby completing the circuit of the relay 12, which in turn causes the transmission of carrier currents lfrom the generator G1, over the front contacts of said relay, to the amplifier TA1. The several generators such as G1, G1, etc., corresponding to different toll lines are arranged to generate different frequenciesthe vfrequency for ythe'line L1 being here illustrated as 4000 cycles.' The carrier currents generated by the generator G1 are amplified by ampliierfTA1'and pass through ailter arrangement TF1 to thetransmitting channelTL. Theilter arrangementTF1 is preferably .al simple tuned; circuit tuned to the Jrequency of the l .channel Whiclr in this instance is L,000 cycles. rents impressed upon ithe'ichannel TL are transmitted' over the common branch` GB, through the ftilter HF to the-line L1, Without reacting upon .the receiving Ichan-nelT RL, since the latter is Jconfjugateewith respect to the channel TL.

Atfifthereceiving station the carrier'currents transmitted-over the 'line actuate receiving apparatus in a manner which will be understood" from adescription Vof theoperationtakingf-placeat the station illustrated, is response-tto carrier currents transmitted fromcthe distant station. 'Such carrier acurrents pass through the tilter HF and through the transformer X t0y the receiving channel RL, from lwhich point l.they pass into receiving branch` RL1, corresponding to the toll vline L11through aiiilterarrangement RF1, which' may besimilarin all-respects to the lter-arrangement TF1 already referred te.` The received'currents are :then amplified by theamplitier'RAf1 and detected bythe detector D1, sof thatdirect current :rela-y R1 :is actuated. Relay R1 :at its upper vfront contacts `completes a `locking circuit through its `locking Winding yover the back contact otrelay 10,*ithrough'thelamp L1 to battery. The lampv yis ithereby icausedto glow, .in-torm- 4ingv the operator that a call: has come in fronr the oppositeendof the-line. *Upon insertingnthe plugro'f ay toll cord fin thejack J 1, lthe 'lamp 'L1 is retired and the relayy R1 released; A re-ningfsignai incoming from the distant ystation will actuatef the` relay R1 .insa similar manner, therebyshunting the sleeve relay 1,0 toeoperate the supervisory .lam-p oty the toll cord, linA ai manner similar -to that described' inconnection with Figurel.`

It .awplug is inserted in the jack :off 'the4 line L2, (not shown) :and ringingl Acurrent is Ytransmitted @t said line, the ringing relay of said line operates to cause the .actuation ofthe .relay Q2, thereby causing carrier current trom thefgenerator Gr2 to be amplified and transmitted tothe-receiving channel RL and thence through' the transformer varrangement X and high pass iilter HF to the line L1. It will benotedtin this connection thattheringingsignal originated at the line 2 is thus transmitted over the line L1, after being translated into carrier currents of ythe frequency assigned to the line L2, Whichl is herein illustrated as 4,500 cycles.

A ringing signalY originating at the opposite endet the lineL2 will, in `asimilar manner, be translated and transmitted to the line L11 by :apparatus 'at theother-end The `carrier cue ofthe fliine. Upon receiving the carrier oscillations-thus transmittedwover thenline L1, said :oscillatinns pass through the filter HF and through the ltransformer X to the recciving circuit RL, `from which `point they are ybranched through the Afiltering arrangementV RF-2 Which is ltuned to 4,500 cycles, to the ampliiier RAZ. The'carrier kcurrents are then amplified, detected by the detector andactuatelthe receiving relay R2 associated with thefline L1, thereby actuating Signalap.- paratus similar to that illustrated in connection with theline L1.

ltigures` and` 3A illustrate the invention asapplied toa .callseifrcuittollline; In order, to understand the diagram, the two sheets containing these` figures -shouldibe placed rend toend. Thecallwcircuitj toll lineL1 tenminates'attheoutgoingfendl in a Ijack J1,;adapt edto cooperate with the vplugot a 'totlcord and, atV itsL incoming end, ,terminates in a plug P1..,.ada.ptedxtecooperate with thejack of a toll switching trunk. Inasmuch :as a larger number vof supervisory signalsy must be transmitted formeach `line in connection with':thenestablishment of a'connection over such` line, itis necessarywto assign a .larger number ofV carrier 1 channels to f each line. As illustrated, the cantaor-"branch CB has .associatedatherewith two transmitting circuits and` one'receivingzcircuit for 'each :linejat the outgoing station, lWhile the carrier ibranch QR" thas associatedthereivith tivo receiving `circuits zand :one transmitting circuit .at the incoming end yot each lrne;` tor'fmstance, at

the ront'going'end transmitting channels TL1 and 'lll-111*hauing:frequencies :at 4,000` cycles an d-4i,500 icycles respectively, `are assigned Ato tlhe line` L1, c while transmitting `channels TL2 -anclv'llI/J12 ot'i5,000icycles and15,500icycles respectively, are assignedxto the line L1. LikeyWise, the receiving' channel RL1 et' v4,000

cycles frequency randthe receiving channel 4Ril-i1, @5,000 cycles frequency are assigned te thewlines L1 and L, respectively. At the .incoming end receiving channels yIRL( and IRL11 `are associated with the linel L1 and corresponding channels RL," and RL21 are Iassociated Wil'hthe line L1. The transmit- `ting channels "lL1I and TL1 are also associated with lines L1 and L111fespectively at their Lincoming ends. The frequencies ot' Athese several `channels will vbe as indicated in the drawing, although` it will :be` understood that the particular frequencies indicat- "ed upgonz'the-dravving are'merely illustrative and that in practice other frequencies than those indicated ymaybe used.

When the originatingoperator has passed the details of the desired connection over xthe callcireuit (not showni), to the tandem position at the incoming endofithe line andhas received the toll assignment, .she .inserts Ithe plug of atell cord Tinto the j ackiTn/thereby @painting .the sleeve relay l0, which .at l,its

Cil

righthand front contact completes the circuit of relay 13. Oscillations from the generator G1 are now transmitted over the front contacts of relay 13, amplified by the amplilier TA1 and pass through the tuned circuit TF l to the transmitting circuit TL and thence through the transformer arrangement X to the carrier branch CB. The oscillations are then passed through the high pass filter HF and transmitted over the toll line L1 through the filter HF to the carrier branch CB at the incoming end. From this point they are transmitted through the transformer arrangement X t0 the receiving circuit RL and thence into the receiving channel RLl through the tuned circuit RF1. After being amplified by the amplifier RAl, they are detected by the detector D1', so that the receiving relay R1 is operated. This relay, at its front contact, completes the circuit for the guard lamp Ll, the circuit of the guard lamp passing over the lower back contact of the'sleeve relay 10;

The incoming operator, upon observing the glowing of the guard lamp L1', inserts the plug P1 into the jack of a toll switching trunk, thereby causing the sleeve relay 10 to be actuated to open the circuit of the guard lamp. Vhen the toll switching trunk has been connected to the subscribers line, battery is connected to the toll switching trunk in a wellknown manner, so that direct current flows from the toll switching trunk over the tip and ring contacts of the plug P1 upper make contact of sleeve relay 10, back contacts of the ringing relay 15, to the Windingof the direct current bridge relay 1G. Relay 16 is therefore actuated and completes the circuit of relay 17, whereby oscil* lations are transmitted from the generator G1 over the front contacts of relay 17 to the amplifier TA1. Upon being amplified, the oscillations are passed through the tuned circuit TF, and over the transmitting circuit TL through the transformer arrangement X to the carrier branch CB. The oscillations then pass through the highpass filter HF and are transmitted over the toll line Ll and through the filter HF to the carrier branch CB. From this point they are transmitted through the transformer X to the receiving circuit RL, from which they are selected by the tuned circuit RF, and pass to the amplifier RAF After being amplified, the oscillations are detected by the detector D1, so that the direct current relay Rl is actuated. The relay R1 connects a shunt about the high resistance winding of` the sleeveY relay 10, thereby causing the actuation of supervisory lamp in the toll cord, in a manner similar to that described in connection with Figure 1.

The outgoing operator, upon receiving this signal, applies ringing current over the tip and ring contacts of the jack J1, thereby actuating the ringing responsive relay 11. The actuation of relay 11 completes the circuit of relay 14, so that oscillations from the generator G1, flow over the front contacts of said relay, through the amplifier TAH, through the filter TFH, over the circuit TL, through the transformer arrangement X, through the high pass filter HF, over the toll line L1, through the filter HF', through the transformer X into the receiving circuit RL, from which point they are selected into the channel RLM, by the filter RFM. The oscillations are then amplified by the amplifier RAM and detected by the detector Du', with the consequent actuation of relay R11. Relay R11 at its upper front contact completes the circuit of the ringing relay 15, which at its front contact applies ringing current over the tip and ring contacts of the plug P1 and over the toll witching trunk to the called subscribers As soon as the called subscriber answers the ringing signal by removing his receiver from the switch hook, the direct current is disconnected from the toll switching trunk, in a well understood manner, thereby causing the de-energization of the relay 16. Oscillations are no longer supplied from the generator Gf, to actuate the relay R1 at the outgoing end of the line, so that said relay is deenergized, thereby removing the shunt lfrom the sleeve relay 10 and extinguishing the supervisory signal' of the outgoing operators cord circuit, thus indicating to the operator that the called subscriber has answered. Should the called party flash his switch hook, thel relay 16, will be intermittently operated by the alternate connection and disconnection of `direct current to the toll switching trunk. Consequently, successive groups of oscillations of 4,000 cycles frequency `will be transmitted from the generator G1', thereby intermittently operating the receiving relay R, at they outgoing operators position. This results in intermittently shunting the sleeve relay, with the consequent flashing of the supervisory signal inthe operator-s toll cord. Y

Vhere it is desired to take the connection down, the originating operator withdraws the plug of the toll cord from the jack J,. This operation releases the sleeve relay 10, which in turn releases the relay 13, so that oscillations of 4,000 cycles frequency from the generator G, are no longer transmitted over the line L1 to maintain the receiving y at the incoming end operated. Said relay is therefore de-energized and at its upper back contact completes the circuit from ground, over the lower front contact of sleeve relay 10 and through the guard lamp L1 to battery. The guard lamp now glows, indicating to the incoming operator that the connection is to be taken down. The plug P1 is therefore withdrawn from the toll switching trunk and the guard lamp L1 is extinguished. The apparatus is now in normal condition.

The operations incident to the establishment of a call over the toll line 'IL2 (not shown) are similar to those already described, except that in this case the carrier channels TL2, TL22 and RL, at the outgoing end, together with the corresponding channels RL2 and RL22 and 'IL2 at the incoming end, are utilized for transmitting the signals. The carrier frequencies are, however, transmitted over the toll line L, and not over the toll line L2. The latter line is therefore available for the superposition of carrier channels for other purposes.

It will be seen that by means of this invention an eflicient and simple means is provided for transmitting supervisory signals in connection with toll lines.

It will also be obvious that the general principles of the invention herein disclosed may be embodied in many other organizations widely different from those illustrated, without departing from the spirit of the invention as defined in the following claims.

What is claimed is:

l. In a signaling system, a low frequency telephone transmission line, a plurality of carrier channels associated therewith for the transmission of frequencies without the voice range, and means whereby, when the operator initiates a supervisory signal of one character, alternating carrier currents will be transmitted over said line through one of said channels and when the operator initiates a supervisory signal of another character, carrier currents will be transmitted over said line through another channel.

2. In a signaling system, a low frequency telephone transmission line, a plurality of carrier channels associated therewith, means whereby, when the koperator initiates a guard signal, alternating carrier currents are transmitted over said line through one of said channels, and means whereby, when the operator initiates a ringing signal, carrier currents are transmitted over said line through another channel.

3. In a signaling system, a low frequency telephonie transmission line, a carrier circuit associated with said line, for transmitting in either direction over said line super visory signals incident-al to the establishment of low frequency telephone connection over said line and means at terminal stations of said line for separating oppositely directed carrier transmissions, said means comprising a pair of separate circuits for the oppositely directed transmissions, said circuits being associated with each other and with the telephone line, through a balancing arrangement comprising a balanced transformer and a balancing artificial line.

4. In a signaling system, a group of telephone transmission lines, and means associated with a special one of said lines for transmitting supervisory signals for all of said lines, said means comprising alternating current carrier channels associated with said special lines and employing frequencies Without the voice range, each of said carrier channels being individual to a corresponding telephone line of said group.

5. In a signaling system, a group of telephone transmission lines, a plurality ofcarrier channels associated with a special one of said lines, each of said carrier channels being individual to a corresponding line of said group, and means whereby inresponse to the initiation of a supervisory signal for any one of the lines of said group, alternating carrier currents without the voice range will be transmitted over said special line through the carrier channels corresponding to the line in connection with which the supervisory signal originated.

6. In a signaling system, a group of telephone transmission lines, a group of carrier channels associated with a special line of said group, said group of carrier channels being divided into subi-groups and' each sub-group being individual to a corresponding telephone line of said group of telephone lines, means whereby when a supervisory signal of one character is initiated in connection with any one of said telephone lines, alternating carrier currents are transmitted over said special lines through one of the carrie-r channels in the sub-group corresponding to the line with which the supervisory signal originated, and means whereby when a supervisory signal of another character is initiated in connection with the same line, alternating. carrier currents will be transmitted over said special line through another channel of the same sub-group.

In testimony whereof, I have signed my name to this specification this 15th day of September, 1919.

LYMAN F. MOREHOUSE. 

